Battle of Cynwit

The Battle of Cynwit was fought in 878 during the Viking invasions of England. The Viking army of Ubbe Ragnarrsson landed in Devon with the goal of assisting Guthrum's East Anglian invasion of Wessex, but Ubbe's army was defeated and destroyed in a West Saxon surprise attack along the Severn River near the fortress of Arx Cynuit.

Guthrum's invasion
In 876, the Danish warlord Guthrum, King of East Anglia, seized the English fortress at Wareham with assistance from Ragnar Ragnarsson's Irish Vikings. King Alfred the Great marched on Wareham with an army, besieging the fortress and giving Guthrum a month to await a fleet which would evacuate his men; the Anglo-Saxons and Danes also exchanged hostages as a sign of good will.

Guthrum secretly bought time so that Ubbe Ragnarrsson and his Viking fleet could return from campaigning in Ireland, where Ubbe had been fighting to avenge the death of his brother Ivar the Boneless. When Ubbe's fleet arrived on the Severn River, Guthrum breached the peace by having nine of the ten hostages executed; the tenth one, Uhtred of Bebbanburg, escaped with the help of his old friend Ragnar. Uhtred then lit a warning brazier which alerted the Anglo-Saxons to the arrival of Ubbe's fleet, and the West Saxons prepared to face two threats.

King Alfred's plans
King Alfred decided to lead one army south from Winchester to deal with Guthrum's invasion from London, while Alfred sent his ealdormen Odda and Wulfhere to the Severn River to block Ubbe from entering into the heart of Wessex. Their soldiers, consisting of hastily-assembled fyrdmen, were poorly-armed, with half of them carrying reaping hooks instead of swords or spears. They decided to take up a position on a hilltop near the fortress of Arx Cynuit in Devon, where Ubbe's fleet had made landfall. Unfortunately for the West Saxons, they would not be joined by Alfred until he was victorious over Guthrum, and the West Saxons were also short on food, having only four days' worth of provisions.

Ubbe sought to attack the Anglo-Saxons, and his sorcerer Storri told him that the Anglo-Saxons would be weak if he attacked. Odda decided to negotiate with Ubbe before the battle, where he made it clear that he would not surrender. Uhtred - who had joined the West Saxon army in time for negotiations - angered Ubbe by saying that Ubbe would die in the coming battle, and a furious Ubbe quit the negotiations. Uhtred's actions, however, were a part of a ploy to make Ubbe doubt his fortune teller's words, buying time before Ubbe would attack next. Uhtred planned a strategy to turn the tide against the Danes: as the Anglo-Saxons were in danger of being outflanked by the Danes if they charged into battle, Uhtred decided to outflank the Danes by burning their ships, creating panic in the Danish camp. This would prevent the Danes from forming a shield wall in time to face the main Anglo-Saxon attack.

Battle
Shortly after Uhtred left on his solo sabotage mission, Odda gave cryptic orders to his captains Leofric and Wulfhere, simply telling them to prepare their men (and refusing to tell them what for, even if it was for battle). Odda's son, Odda the Younger, attempted to dissuade his father, asking his father to join Alfred's army at Winchester so that they could destroy Ubbe's army together. However, Odda had sworn to attack at the first sight of fires on the Danish ships, and he went along with Uhtred's plan.

Uhtred, by himself, snuck into the Danish camp and was able to firebomb the Danish longships before yelling about the fires and creating panic. Several Danes were killed while attempting to put out the flames, as the water only spread the fires on the decks. Before Uhtred could escape, he found a hastily-dressed Ubbe, who had left the company of prostitutes in his tent after Storri alerted him to the fires. Ubbe then challenged Uhtred to a duel, and Ubbe had the upper hand until Uhtred cut deep into his thighs with a knife, slashed him with a sword, and then plunged the sword into his chest, killing him. Just as the Vikings were about to attack Uhtred, the West Saxon soldiers attacked down the hill, and Odda had them form a shield wall. The West Saxons routed and destroyed the confused Danish army, but Odda suffered a severe head wound in battle, leaving his son Odda the Younger as acting ealdorman.

Aftermath
Uhtred ordered Ubbe to be buried with his axe in a dignified manner, as he was the greatest warrior whom he had heard of; this went against Odda the Younger's desires to have him dismembered. Unfortunately for Uhtred, Odda the Younger took credit for the victory, and Uhtred was chastised by King Alfred when he objected. In the end, the Battle of Cynwit proved to be a relief for Alfred, who would now only have to face Guthrum's invasion, which nearly brought an end to Wessex.